This invention relates generally to the art of automated packaging of materials and particularly to a machine for capping containers.
Chemical products in liquid form, such as herbicides, insecticides, oil, grease, and other chemicals, are often packaged and sold in five-gallon drum containers. The five-gallon drum containers or cans are generally cylindrical in shape with a flat top and bottom. A folddown handle is generally provided in the middle of the top of the can and a circular opening for filling and emptying the can is also provided in the top adjacent the edge of the can. The can is sealed for shipment and storage by capping the opening in the top of the can.
Conventionally, the circular opening in the can has an outwardly protruding ridge around its circumference. A cap having deformable metal edges is placed over the opening, and the edges of the cap are crimped onto the protruding ridge to attach the cap securely to the can and thereby to seal the can.
In order to open the can to empty the contents, the cap has a removable center portion. The center portion can be threaded or adapted to be pried open. The center portion of the cap may also have a retractable spout to facilitate pouring of liquid material from the can.
In the past, capping the can by crimping the cap over the ridge of the opening was accomplished by hand using a hand held crimping tool or crimper. The person, whose job was to cap the can, had to assure that there was a cap placed over the opening, that the cap was properly seated upon the ridge around the opening and that the crimper was properly seated upon the cap so that when the cap was crimped, a secure seal was made.
The capping procedure defied attempts at automation for several reasons. First, the cans varied in height by as much as a quarter of an inch from the nominal height. Furthermore, the tops of the cans were often tilted or were concave or convex as opposed to being perfectly flat and level. Moreover, the opening was not consistently spaced from the edge of the can or located with regard to the can's handle. These variations made it difficult to accurately locate the opening and thus assure proper placement of the cap over the opening and proper seating of the crimper on the cap.
Also, the caps varied in their consistency of quality. It was not uncommon to receive caps from manufacturers which were twisted or bent so that they did not properly seat on the ridge prior to crimping. It was therefore necessary for a human to assure that all parts of the cap and ridge were properly seated and that the crimping tool was properly seated on the cap in order to assure a reliable seal of the cap on the can.
If an automated capping machine fails to assure proper seating of cap and crimping tool and the crimping operation occurs, an improper seal may be made. Such a seal may leak during storage and shipment thereby creating a potential hazard if the chemical is toxic or flammable.
Also improper seating of the cap and crimper prior to crimping may damage the opening's ridge so that the container cannot by properly sealed subsequently.
Therefore, it is an object of the present invention to provide an automatic capping apparatus which reliably caps cans by allowing for the variations in the height of the cans and the orientation of the opening in the can top.
It is also an object of the present invention to provide an automatic capping apparatus having an aligning mandrel for accurately locating the opening in the can to assure that the caps are reliably placed over the opening and seated on the ridge so that the crimping tool will properly seat on the caps prior to crimping.
It is further an object of the present invention to provide an automatic capping apparatus having a cap placer which can determine whether or not a cap has been placed over the opening of the can.
It is also an object of the present invention to provide an automatic capping apparatus having a flexibly supported crimper with a sensing means attached to it to determine whether or not the crimper has properly seated on the cap prior to crimping the cap.